In various industrial processes, it often is provided to gravity feed fine bulk material through ducts to various types of equipment including valves, mixers, grinders, screeners, storage vessels, receptacles and the like. Often, such ducts are provided with certain forms of barriers to prevent various objects such as tools, machine parts, large pieces of material and the hands of human operators from entering into and extending through such ducts, possibly causing damage to downline equipment, interrupting or deterring the flow of material being processed or causing injury to operators.
In the prior art, there have been a number of such barriers for ducts developed and deployed. However, such prior art devices have been found not to be fully effective in ensuring the free flow of fine bulk material while precluding the passage of large objects such as tools, machine parts and like and preventing the insertion and possible injury to the hands of operators. It thus is the principal object of the present invention to provide a device disposable in the path of a fine bulk material within a duct or other conveyance means, provided with a barrier which will screen out and retain various objects such as tools, machine parts and the like, and prevent the harmful penetration of the hands and arms of operators but will not only allow and facilitate the steady flow of bulk materials but function to disperse agglomerations of such bulk materials deposited on and/or between components of such barriers.